This course introduces acoustics by using the concept of impedance. In the previous part, the course starts with vibrations and waves, demonstrating how vibration can be envisaged as a kind of wave, mathematically and physically. They are realized by one-dimensional examples, which provide mathematically simplest but clear enough physical insights. Then the part 1 ends with explaining waves on a flat surface of discontinuity, demonstrating how propagation characteristics of waves change in space where there is a distributed impedance mismatch.
Following the part 1, part 2 starts with radiation, scattering, and diffraction, which can be explained in a unified way by seeing the changes of waves due to spatially distributed impedance. Lastly, the course covers sound in closed space, which is considered to be a space that is surrounded by spatially distributed impedance, and introduces two spaces: acoustically large and small space.

From the lesson

Waves on a Flat Surface of Discontinuity 1

You will now learn when the waves meet on a flat surface of discontinuity. It will be explained with the mass law of wave phenomena.